Seattle Aquarium mammal biologist Julie Carpenter recently assisted scientists from NOAA’s National Marine Fisheries Service (NMFS) with their pup count, which happens every two years in the Pribilof Islands, Alaska. The Pribilofs are home to the largest breeding colonies (or rookeries) of northern fur seals in the world, representing over half of the world’s northern fur seal population. Collaborating on the research and participating in it side-by-side with the field researchers provided Julie with firsthand experience and knowledge about the research techniques and technical challenges involved in working with the wild northern fur seal population—making her uniquely suited to bring a deeper understanding of this work back to the staff and visitors of the Seattle Aquarium. Through this cooperative relationship, our hope is to continue to educate people about the critical population studies being conducted in these far-off islands and the many issues surrounding the Pribilof fur seals. Learn about Julie’s experience in the Pribilof Islands in this four-part blog series.
Part 2: The long wait for St. Paul, Alaska is over! Pup shearing begins
Finally! After a five-day layover and despite dense fog on St. Paul, we got on a plane and managed to land! A few researchers were able to fly standby earlier in the week and although they were short-staffed, they had to start work without us.
This evening we were briefed on the basics of this long-term “mark and recapture” study. Our job is to “mark” a certain percentage of pups by briefly picking them up and trimming a small patch of the dark, outer guard hairs off the tops of their heads using sheep shearers. This leaves their lighter underfur visible, allowing them to be easily identified from a distance among other fur seals, while still staying warm. In a couple of months, the pups will molt (shed their old fur) and grow new fur that will fill in their haircuts.
We prepped our gear including rain pants and jackets, boots, welding gloves, gauntlets (leather sleeves) and our freshly sharpened shears. We’re ready for the rookeries!
My first time shearing! A few researchers flew to St. George, another of the Pribilof Islands, to shear and count the northern seal pups that were born there this year, leaving a group of 10 of us on St. Paul to finish the work here. There were only 5 of 14 rookeries left to shear: Lukanin, Kitovi, Polovina, Little Zapadni and Polovina cliffs.
To begin, three people went ahead to temporarily move large males and females out of their territories so the rest of us could safely move in with our shearers and give haircuts to some of the pups. The number of pups to shear was determined by the previous year’s count at each rookery. We moved out of the area after shearing pups, allowing the adults to come back to their territories. This process continued as we slowly made our way down each rookery.
Shearing the top of a pup’s head is not exactly intuitive and it took me a while to get the hang of it. I’m amazed by how agile and aggressive the pups are despite how sweet and small they appear. Most pups weighed about 4.0–8.0 kg (about 10–18 lbs).
Pups were sheared and released in under 10 seconds (well, once I got the hang of it). After two days of shearing, I managed to escape with only bruises.
Stay tuned for the next blog post. To learn more about northern fur seals, come visit the Aquarium!
The work described here was authorized under Marine Mammal Permit No. 14327 issued to the National Marine Mammal Laboratory, AFSC, NMFS.